1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Author: Huacai Chen <chenhuacai@loongson.cn> 4 * Copyright (C) 2020-2022 Loongson Technology Corporation Limited 5 */ 6 7 #include <linux/binfmts.h> 8 #include <linux/elf.h> 9 #include <linux/err.h> 10 #include <linux/init.h> 11 #include <linux/ioport.h> 12 #include <linux/kernel.h> 13 #include <linux/mm.h> 14 #include <linux/random.h> 15 #include <linux/sched.h> 16 #include <linux/slab.h> 17 #include <linux/timekeeper_internal.h> 18 19 #include <asm/page.h> 20 #include <asm/vdso.h> 21 #include <vdso/helpers.h> 22 #include <vdso/vsyscall.h> 23 #include <generated/vdso-offsets.h> 24 25 extern char vdso_start[], vdso_end[]; 26 27 /* Kernel-provided data used by the VDSO. */ 28 static union loongarch_vdso_data { 29 u8 page[PAGE_SIZE]; 30 struct vdso_data data[CS_BASES]; 31 } loongarch_vdso_data __page_aligned_data; 32 struct vdso_data *vdso_data = loongarch_vdso_data.data; 33 static struct page *vdso_pages[] = { NULL }; 34 35 static int vdso_mremap(const struct vm_special_mapping *sm, struct vm_area_struct *new_vma) 36 { 37 current->mm->context.vdso = (void *)(new_vma->vm_start); 38 39 return 0; 40 } 41 42 struct loongarch_vdso_info vdso_info = { 43 .vdso = vdso_start, 44 .size = PAGE_SIZE, 45 .code_mapping = { 46 .name = "[vdso]", 47 .pages = vdso_pages, 48 .mremap = vdso_mremap, 49 }, 50 .data_mapping = { 51 .name = "[vvar]", 52 }, 53 .offset_sigreturn = vdso_offset_sigreturn, 54 }; 55 56 static int __init init_vdso(void) 57 { 58 unsigned long i, pfn; 59 60 BUG_ON(!PAGE_ALIGNED(vdso_info.vdso)); 61 BUG_ON(!PAGE_ALIGNED(vdso_info.size)); 62 63 pfn = __phys_to_pfn(__pa_symbol(vdso_info.vdso)); 64 for (i = 0; i < vdso_info.size / PAGE_SIZE; i++) 65 vdso_info.code_mapping.pages[i] = pfn_to_page(pfn + i); 66 67 return 0; 68 } 69 subsys_initcall(init_vdso); 70 71 static unsigned long vdso_base(void) 72 { 73 unsigned long base = STACK_TOP; 74 75 if (current->flags & PF_RANDOMIZE) { 76 base += get_random_int() & (VDSO_RANDOMIZE_SIZE - 1); 77 base = PAGE_ALIGN(base); 78 } 79 80 return base; 81 } 82 83 int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) 84 { 85 int ret; 86 unsigned long vvar_size, size, data_addr, vdso_addr; 87 struct mm_struct *mm = current->mm; 88 struct vm_area_struct *vma; 89 struct loongarch_vdso_info *info = current->thread.vdso; 90 91 if (mmap_write_lock_killable(mm)) 92 return -EINTR; 93 94 /* 95 * Determine total area size. This includes the VDSO data itself 96 * and the data page. 97 */ 98 vvar_size = PAGE_SIZE; 99 size = vvar_size + info->size; 100 101 data_addr = get_unmapped_area(NULL, vdso_base(), size, 0, 0); 102 if (IS_ERR_VALUE(data_addr)) { 103 ret = data_addr; 104 goto out; 105 } 106 vdso_addr = data_addr + PAGE_SIZE; 107 108 vma = _install_special_mapping(mm, data_addr, vvar_size, 109 VM_READ | VM_MAYREAD, 110 &info->data_mapping); 111 if (IS_ERR(vma)) { 112 ret = PTR_ERR(vma); 113 goto out; 114 } 115 116 /* Map VDSO data page. */ 117 ret = remap_pfn_range(vma, data_addr, 118 virt_to_phys(vdso_data) >> PAGE_SHIFT, 119 PAGE_SIZE, PAGE_READONLY); 120 if (ret) 121 goto out; 122 123 /* Map VDSO code page. */ 124 vma = _install_special_mapping(mm, vdso_addr, info->size, 125 VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC, 126 &info->code_mapping); 127 if (IS_ERR(vma)) { 128 ret = PTR_ERR(vma); 129 goto out; 130 } 131 132 mm->context.vdso = (void *)vdso_addr; 133 ret = 0; 134 135 out: 136 mmap_write_unlock(mm); 137 return ret; 138 } 139